Substitutes for Obsolete Parts on NUCLEO-WL55JC (MB1389)

[rohithinthingstech]

Hello ST Community,

I am developing a custom board based on the MB1389 development board and have encountered some obsolete components used in the reference design. Specifically:

1. NX3L1T3157GM,115 is now obsolete. I plan to use NX3L1T3157GMZ as a direct substitute.
2. BGS13S4N9E6327XTSA1 is also obsolete, and I am considering BGS13SN8E6327XTSA1 as a replacement.

I’ve reviewed the datasheets for both substitutes and noted minor differences in parameters such as on-state resistance and channel matching in the NX3L1T3157 variant, and potential RF characteristics in the BGS13S4 replacement.

Could anyone from ST or the community advise if these substitutions are fully compatible with the MB1389 design, or if there are specific implications (e.g., signal integrity, RF performance, PCB footprint) that I should be aware of before finalizing the hardware?

[rohithinthingstech]

hello....any update?

[STTwo-32]

Hello @rohithinthingstech 

even if in the DigiKey website it is stated that ON resistance is 900 mOhm vs 500 mOhm of the obsolete part, in the datasheet I found this difference is not mentioned (I was not able to find the datasheet of the obsolete part, only the generic one for NX3L1T3157GM device.

In any case, from the datasheet, Figure 7, ON resistance is 400 mOhm or lower in the use case when VDD is 3.3V and Vin is up to 3.3V.

Regarding the other part to be replaced, the insertion loss is almost the same for typical values (the max difference is 0.2 dB at 85 degrees Celsius) but the isolation is 2 dB better for the new part. Pay attention to the fact that the pins and the footprint are different.

Finally, I can say that both parts can be replaced with the new ones suggested by the manufacturers.

Best Regards.

STTwo-32